Protecting rice crops at no extra cost

A newly identified genetic mechanism in rice can be utilized to maintain resistance to a devastating disease, without causing the typical tradeoff – a decrease in grain yield, a new study reports. Rice blast is a serious fungal disease that can devastate rice crops. Yet, often genes that provide resistance to the pathogen compromise the yield of rice grains. Previously, researchers had identified a set of genes that enable high and durable resistance to the fungus. Here, Yiwen Deng explored these genes in greater detail, finding that PigmR was particularly effective, providing complete resistance to 50 rice blast variations. If PigmR is expressed while seeds are made, however, this hinders seed production and thus reduces yield, the authors report. They found that co-expression of another gene, PigmS, interferes with the resistance properties of PigmR. Intriguingly, in one strain of rice plants, PigmR was found to be expressed throughout the plant, while expression of PigmS was limited to the reproductive tissues, thus limiting the seed damage associated with PigmR. This site-specific suppression endows the plant with resistance to rice blast in its stem, stalk, leaves, without compromising yield. The researchers also identified specific amino acids that are involved in blocking the function of PigmR. These advancements could help boost protection of rice crops, without altering the rice production quantities.